Question

During a ${360}^{\circ }$ or a complete rotation of a regular triangle, at what angles of rotation is the figure identical to the original figure?

• A. ${60}^{\circ }$
• B. ${120}^{\circ }$
• C. ${180}^{\circ }$
• D. ${240}^{\circ }$

Answer 1

Answer: (B), (D)

${240}^{\circ }$

A regular triangle is nothing but an equilateral triangle. If you join all the vertices to the centre, the central angle is divided into 3 equal angles, each measuring ${120}^{\circ }.$ So, if you rotate the triangle by an angle of ${120}^{\circ }$, it will look identical to the starting position.
Similarly, it will be identical to the original figure on a further rotation of ${120}^{\circ }$ or an overall rotation of ${240}^{\circ }.$